(Bloomberg Businessweek) -- The first-floor apartment on West 37th Street, a few blocks south of Times Square, was popular with tourists—so popular that a set of keys was left at the counter of a nearby bodega for Airbnb renters to pick up. That’s where a 29-year-old Australian woman and a group of her friends retrieved them, no identification needed, when they arrived in Manhattan to celebrate New Year’s Eve in 2015. The apartment h...